1. Field of the Invention
The present invention relates generally to data communications, and more particularly but not exclusively to scanning of data transmitted over computer networks.
2. Description of the Background Art
Computer viruses, worms, Trojans, and spyware are examples of malicious codes that have plagued computer systems throughout the world. Although there are technical differences between each type of malicious code, malicious codes are commonly collectively referred to as “viruses.” For example, commercially available “antivirus software” is designed to scan a computer for viruses as well as worms and other malicious codes.
A computer network may employ an antivirus as a protective measure against viruses. For example, antivirus software may be installed in a gateway, router, or other centralized network component to scan network data (e.g., packets transmitted over the network) for viruses. As a further example, a gateway with antivirus components may scan packets exchanged between a client computer within the network and a server computer outside the network. In that scenario, the gateway is in-line with the client computer and server computer, and scans packets exchanged between the two. Antivirus components capable of in-line virus scanning are commercially available from several vendors including Trend Micro, Inc.
High-availability computing environments are those capable of continuous operation. Typically, in a high-availability environment, network components that provide critical services are deployed with redundancy. For example, redundant network security computers may be employed to scan network data. While deployment of redundant security computers makes the computer network more robust, it complicates in-line scanning because there are several computers available to scan packets leaving and entering the network and improper or lack of coordination between these computers may result in some packets not being scanned at all.